Airworthiness Directive · Amendment 39-11983 · Bell Helicopter Textron, Inc. Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K Helicopters
Bell Helicopter Textron, Inc. Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K Helicopters
Superseded. A later AD replaced this one: AD 2001-17-17. Comply with the one in force.
Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K helicopters, with main rotor blade grips, part number (P/N) 47-120-135-2, 47-120-135-3, 47-120-135-5, 47-120-252-1, 47-120-252-7, 47-120-252-11, 74-120-252-11 and 74-120-135-5, installed, certificated in any category.
Note 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This document publishes in the Federal Register an amendment adopting superseding Airworthiness Directive (AD) 2000-18-51 which was sent previously to all known U.S. owners and operators of Bell Helicopter Textron, Inc. (BHTI) Model 47B, 47B-3, 47D, 47D-1, 47G, 47G- 2, 47G2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G- 4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K helicopters by individual letters. This AD requires recurring liquid penetrant or eddy current inspections of the main rotor blade grip (grip) threads for a crack. If a crack is detected, this AD requires, before further flight, replacing the cracked grip with an airworthy grip. This AD also establishes a retirement life of 1,200 hours time- in-service (TIS) for each grip. This amendment is prompted by the results of an investigation of an August 1998 accident in which a grip failed on a BHTI Model 47G-2 helicopter due to a fatigue crack. An analysis of the field service data revealed fatigue cracks in 70 percent of the grips inspected. The actions specified by this AD are intended to prevent failure of a grip, loss of a main rotor blade, and subsequent loss of control of the helicopter.
To prevent failure of a main rotor blade grip (grip), separation of a main rotor blade, and subsequent loss of control of the helicopter, accomplish the following:
(a) Within 100 hours time-in-service (TIS) since initial installation on any helicopter or within 10 hours TIS for grips with 100 or more hours TIS, conduct a liquid penetrant or eddy current inspection of the grip threads for a crack. Thereafter, conduct the liquid penetrant or eddy current inspection at intervals not to exceed 200 hours TIS. If a crack is detected, before further flight, replace the cracked grip with an airworthy grip.
(b) On or before 1200 hours TIS, replace each grip with an airworthy grip. This AD establishes a retirement life of 1200 hours TIS for grips, P/N 47-120-135-2, 47-120-135-3, 47-120-135-5, 47-120-252-1, 47-120-252-7, 47-120-252-11, 74-120-252-11, and 74-120-135-5.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
